Current sources



March 28, 1933. R. RECHNITZER CURRENT SOURCE 5 Filed Nov. 14, 1929 INVENTOR RUDOLF RECHNiTZER 7 ATTORNEY Patented Mar. 28, 1933 tsmz m.

UNITED STATES PATENT OFFICE RnDoLR RRenNItrzn or BERLIN, GERMANY, ASSIGNOR '10 TELE U RRN eEsELL:

SGHAFT Fl 'R DRAHTLOSE TELEGRAPHIE M. B. IL, 0] BERLIN,

RATION OF GERMANY CURRENT SOURCES Application filed November 14, 1929, Serial No. 407,097, and in Germany November 8, 1928.

This invention relates to means for supplying direct current free from alternating cur-. rent components to the filaments of ther mionic tubes, and in particular to apparatus of the above nature inwhich the various elements are arranged in a novel manner such that highly improved results may be obtained with apparatus of reduced size.

The invention has been illustrated'in the attached drawing in which,

Figure 1 shows a filter circuit interposed between a source of current and a load;

7 Figure 2 shows a filter circuit arranged. in accordance with applicants novel invention; while, i 3

Figure 3 shows a modification of the arrangement of Figure 1.

When supplying the filament current for thermionic tubes from a rectified alternating current source or a pulsating direct current source rectifier, direct current network). it is necessary to free the direct current from alternating current components. With this end in view mostly one or more filter chains are employed, for instance, in a circuit arrangement of the kind shown in Figure 1, where E and e the direct current and the alternating current components of the supply or feed potential, L a choke-coil, G a shunt or parallel condenser, R a series resistance, and W the load resistance, i. e., the resulting filament resistance. of all of the tubes.

A simple calculation shows that the relation M between the alternating current component e across the terminals of load W and the alternating current component e of the source, when relatively highv direct current component is very considerably diminished so that it must be made of relatively large dimensions. Furthermore, C must become Very high whenever R+W becomes small, i. e., when relatively large filament currents have to befsupplie Since, for instance,in receiversthe tubes take dissimilar filament currents, with the largest current beingrequired by the last tube or the power stage (which furthermore, because of low amplification is comparatively insensitive to the alternating current component of the .filament current), recourseis had to the scheme shown in'Fig. 2 with the end in view of diminishing the biasing magnetization of the choke-coil L by the direct current. Referring toFig.2,jw and a denote, respectively, the filament resistance of the input tubes and-the power tubes, and 7* and 7" the corresponding series resistances. W hat flows here exclusively through the choke-coil L is thefilament current of the input tubes which is considerably lower than that of the end or power stage.

However, this circuit arrangement involves the drawback that here two series resistances are required, and that the energy dissipated therein is comparatively large.

Now, according to the invention arrangements are so chosen that the total filament current is made to flow through a joint see rles resistance and that the choke-coil is included only in the lead of the filament circuit of all or part of the input tubes, ina way as shown in Fig. 3.

This arrangement not only allows ofcom bining the advantage'residing in a reduction of the biasing magnetizing current of the choke-coil L withthe advantage of saving GERMANY, A GORPO- 1",, as in Fig. 2, but it is also feasible to dispense with the parallel condenser C or. to

reduce the size of the same considerably inasmuch as the potential distribution asregards the input tubes-is fundamentally different. In practice the reduction ratio]- of the alternating current components of the tion ratio potential is far more favorable than in the circuit schemes hereinbefore indicated.

There is in thiscase:

. "r+u= r (2) presuppo'sing that wL 10.

Furthermore to W m From (2) and (3) there follows thisreducsuperiority of the circuit scheme here disclosed follows from the relation In practice there is w wand u=W, furthermore 1"=R, whence i .6011 IEW In practice it is possible to'put with sufiicient approximation:

Hence, the circuit schemes here compared result 1n slmilar reductlon ratios when i v wL For instance, if w amounts to around 100 ohmand this is frequently the casethen the circuit scheme shown in Fig. 1, in order T to be equivalent as regards reduction ratio,

would have to contain a condenser C of 30 mfd., at 50 cycles, and of 3 mfd. at 500 cycles. Hence,in' the circuit arrangement of this invention there is saved a condenser of 30 and 3 mfd., respectively, under conditions as cited in the above numerical example.

I I claim:

1. In apparatus for supplying the filaments of thermionic tubes having different amplification factors, a source of pulsating direct current, means for connecting the filaments of the high amplification tubes in series through an inductance and resistance with said source,and means for connecting the remaining tube filaments through said resistance in series with said source.

2. Means for supplying heating currents to the emission elements of aplurality of thermionic repeaters of signaling apparatus, from a source on which alternating current components are superposed and for preventing said components from modulating the repeated signals, including a source of current having alternating current, components superposed thereon, a filter inductance, means for connecting the emission elements of the'tub'es in the first of said repeaters in series with said source and said filterinductance, aresistance, and means for connecting the emission elements .of the tubes in the last of said repeat ers in series with said resistance, said filter inductance and with said source.

3. Means for supplying heating current to the emission elements of a plurality of repeater stages, each stage comprising at least one thermionic tube, the tubes of the initial stages having greater amplification factors than the tubes of the remaining stages, froma source of energy including alternating current com ponentsrand for preventing said components from'modulating the repeated signals com prising a resistance, a filterinductance,means for connecting the emission elements of the tubes having high amplification factors in series with said inductance said resistance and said source, and means for connectlng the emisslon elements of the other tubes in series with said resistance and said source.

f 4. In signalling apparatus comprising a plurality of space discharge devices some of which are utilized for high amplification purposes While others are utilized for low amplification purposes, means for energizing the cathodes of all of the space discharge devices comprising a source of fluctuating direct current, a resistance element, filtering I means, means for forming a'series circuit comprising the cathodes of the high amplification devices,

the filtering means, the resistance and said source, and means for shunting the cathodes of the low amplification devices across the portion of the series circuit including the filtering means and the cathodes of thehigh amplification devices. I

' RUDOLF RECHNITZERV 

